Switch-mode circuits, including switch-mode power supplies and motor controllers, are pervasive in many electronic applications from computers to automobiles. Generally, voltages within a switched-mode power supply system are generated by performing a DC-DC, DC-AC, and/or AC-DC conversion by operating a switch coupled to an inductor or a transformer. Switch-mode power supplies are usually more efficient than other types of power conversion systems because power conversion is performed by controlled charging and discharging a low loss component, such as an inductor or transformer, therefore reducing the energy lost due to power dissipation in resistive components. Similarly, switch-mode motor controllers may be used to efficiently commutate DC brushless motors with low losses in the driving circuitry.
With respect to implementing a switch-mode circuit, specialized driving circuitry is used to efficiently drive a switching transistor coupled to the various magnetic components. Such circuitry may be configured to provide switching signals at appropriate speeds and voltage levels. These voltage levels may be established, for example, by using external DC supply voltages, voltage regulators, level shifters, charge pumps and other circuits to ensure that the switching transistor is turned-on and off. In addition to establishing appropriate voltage levels, switching transistor driving circuits may also be designed to mitigate the effects of voltage transients caused by the fast switching of inductive loads. Such effects may include, for example, voltage overshoot seen at the switching transistor and/or the ringing or oscillations due to stray inductance and parasitic capacitance.